What happened
On June 29, 1998, a Piper PA-28RT-201, registration PH-JAW, was conducting a VFR flight from Rotterdam to Le Touquet/Paris Plage, France. During the flight through Belgian airspace, the pilot experienced an electrical failure characterized by a loud crackling sound, which subsequently disabled the onboard navigation and communication equipment. Due to the loss of radio capabilities, the pilot diverted to Midden-Zeeland Airport.
Prior to landing, the pilot attempted to extend the landing gear. While the gear appeared to lock, the cockpit instrument lights remained dark due to a total electrical failure. In an attempt to verify the gear's position, the pilot used a mobile phone to contact the local harbor master. During the approach, while managing the aircraft and communicating via telephone, the aircraft's speed dropped significantly. At approximately 40 feet altitude, the aircraft entered a stall and struck the ground heavily on the landing gear, causing the gear to collapse and the fuselage to slide along the terrain.
The investigation
The investigation focused on the cause of the electrical failure and the circumstances leading to the loss of control. Investigators found that the aircraft's battery capacity had dropped to approximately 20%, rendering it nearly depleted. The failure was traced to a broken V-belt on the generator. Notably, the aircraft's air conditioning system was active, which required a narrower belt that was more prone to slipping and breaking due to space constraints in the engine cowling.
Furthermore, the investigation examined the pilot's actions during the emergency. It was determined that the pilot did not follow the prescribed emergency checklists for a generator failure. The investigation also noted that the stall warning system was non-functional due to the low battery voltage, meaning the pilot received no auditory warning of the impending stall.
Findings
- The primary cause of the accident was the reduction of airspeed below the stall threshold, which led to the aircraft entering a stall during the final approach.
- The electrical failure was initiated by the breakage of the generator's V-belt, preventing the battery from recharging.
- The pilot failed to recognize the nature of the electrical malfunction, mistakenly assuming a short circuit had occurred rather than a generator failure.
- The pilot's attention was diverted by the simultaneous management of the landing gear concerns and the use of a mobile phone to communicate with ground personnel.
- The stall warning system was inoperative because the battery voltage was too low to power the system.